In a
single 140-character broadside, Trump declared that Rubio's
middle name was "amnesty," highlighted his poor Senate voting
record, and suggested the senator didn't have
a foreign-policy "VISION" for the country.

With that tweet, Trump has now insulted almost every single one
of his Republican rivals on Twitter.

The online trash-talk, which has become a featured method for
Trump, usually comes in response to a shot fired by the opponent
in question. Rubio, for example, recently said Trump
had not provided enough specifics on national security.

Only a couple of candidates who refuse to criticize Trump have
escaped unscathed — notably Sen. Ted Cruz (R-Texas), Ohio Gov.
John Kasich (R), and former Arkansas Gov. Mike Huckabee (R). New
Jersey Gov. Chris Christie (R), who has taken light
shots at Trump but calls him a friend, has also largely
avoided Trump's ire outside of some retweets
attacking him.

Retired neurosurgeon Ben Carson

Trump unleashed a storm
of criticism against the soft-spoken doctor after he
said Trump was not as publicly religious as himself. Carson
retracted his comments and Trump backed off as a result,
only going after Carson's poll numbers and retweeting a supporter
attacking his energy.

Wow, I am ahead of the field with Evangelicals (am so proud of this) and virtually every other group, and Ben Carson just took a swipe at me

Former Florida Gov. Jeb Bush (R)

Bush, another frequent Trump critic, is probably Trump's favorite
target on Twitter. Trump has released multiple
social-media attack ads against Bush and constantly
taunts the former governor with gusto on a wide range of
issues.

Louisiana Gov. Bobby Jindal (R)

Jindal recently launched an all-out assault against Trump,
calling him an "egomaniacal madman," questioning his
conservatism, and much more. Trump initially said he wouldn't
respond to someone so low in the polls — but eventually blasted
him on Twitter.

Oh wow, lightweight Governor @BobbyJindal, who is registered at less than 1 percent in the polls, just mocked my hair. So original!